Explanation
Provision an Aurora Replica in a different Region will meet the requirement of the application being able to recover to a separate AWS Region in the event of an application failure, and no data can be lost, with the least amount of operational overhead.

Explanation
https://docs.aws.amazon.com/vpn/latest/clientvpn-admin/scenario-peered.html

Explanation
According to the AWS documentation1, to access a private API from a VPC, you need to do the following:
Create an interface VPC endpoint for API Gateway in your VPC. This creates a private connection between your VPC and API Gateway.
Attach an endpoint policy to the VPC endpoint that allows the execute-api:lnvoke action for your private API. This grants permission to invoke your API from the VPC.
Enable private DNS naming for the VPC endpoint. This allows you to use the same DNS names for your private APIs as you would for public APIs.
Configure a resource policy for your private API that allows access from the VPC endpoint. This controls who can access your API and under what conditions.
Use the API endpoint's DNS names to access the API from your VPC. For example,
https://api-id.execute-api.region.amazonaws.com/stage.

Explanation
This solution will improve the reliability of the application by addressing the issues of scalability, availability, and performance. Containerizing the application will make it easier to deploy and manage on AWS. Migrating the application to an Amazon ECS cluster will allow the application to run on a fully managed container orchestration service. Using the AWS Fargate launch type for the tasks that host the application will enable the application to run on serverless compute engines that are automatically provisioned and scaled by AWS.
Creating an Amazon EFS file system for the static content will provide a scalable and shared storage solution that can be accessed by multiple containers. Mounting the EFS file system to each container will eliminate the need to copy the static content to each EBS volume and ensure that the content is always up to date.
Configuring AWS Application Auto Scaling on the ECS cluster will enable the application to scale up and down based on demand or a predefined schedule. Setting the ECS service as a target for the ALB will distribute the incoming requests across multiple tasks in the ECS cluster and improve the availability and fault tolerance of the application. Migrating the database to Amazon Aurora MySQL Serverless v2 with a reader DB instance will provide a fully managed, compatible, and scalable relational database service that can handle high throughput and concurrent connections. Using a reader DB instance will offload some of the read load from the primary DB instance and improve the performance of the database.

Explanation
Deploying the application on Amazon EKS with managed node groups simplifies the operational overhead of managing the Kubernetes cluster. Running the web servers and application as Kubernetes deployments ensures that the desired number of pods are always running and can scale up or down as needed. Storing the frontend web server session data in an Amazon DynamoDB table provides a fast, scalable, and durable storage option that can be accessed across multiple Availability Zones. Creating an Amazon EFS volume that all applications will mount at the time of deployment allows the application to share data that is frequently accessed between the web and application tiers. References:
https://docs.aws.amazon.com/eks/latest/userguide/managed-node-groups.html
https://docs.aws.amazon.com/eks/latest/userguide/deployments.html
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Introduction.html
https://docs.aws.amazon.com/efs/latest/ug/mounting-fs.html